thermocouple measurement error of causes

In the working process of thermocouple, it is found that in some cases, there are always some errors in its measurement. What are the main factors affecting these errors? In this regard, we will give some answers in this paper, hoping to help you better understand the thermocouple product.

In view of this problem, we can consider seven factors, and we will introduce them one by one. It is caused by the unstable thermoelectric characteristics of thermocouple. After a period of use, especially the impact of the environment, its own performance will have some changes, resulting in a certain difference between the measurement temperature and the real temperature. Second, because of the non-uniformity, mainly refers to the uniformity of the thermoelectric electrode material.

In addition to the above two aspects of the problem, if the measured temperature point is different, it will also lead to certain differences. In fact, in the installation of thermocouple, the selection of temperature measurement point is a very critical issue, we must fully consider, and then select a representative temperature measurement point. The fourth is the effect of response time. Generally, when the temperature of the measured object is consistent with that of the temperature measuring element, the temperature of the temperature measuring element will remain stable.

In addition, thermal radiation needs to be considered. We know that the increase of temperature is not only the heat transfer, but also the change of temperature caused by thermal radiation. Therefore, when the thermocouple is used to measure the temperature in the furnace, the high-temperature objects in the furnace will produce certain thermal radiation, which will cause the temperature to rise and form errors. In addition, if the ambient temperature is high and it is in such condition for a long time, the thermal impedance of the protection tube will increase, and then the measurement error will be increased.

One aspect that should be considered is that the thermocouple wire is not homogeneous, resulting in errors. Therefore, in the production and processing, we need to pay attention to this problem, try to avoid the impact of this problem.